I've been asked on another forum to
1. stop using {0,1} and use the optional operator (?), the reason being that it's easier to read for the "properly" trained regexp specialists.
2. use non capturing groups (?:) when possible, to speed up matches a little (because the regex engine does not need to keep track of groups).

So, you have below the functionally equivalent regex, but a little more "canonically" written: